Cheng YS, et al. – The aim of this retrospective study was to examine distinguishing characteristics of chronic bronchitis (CB), emphysematous (EM) and asthma–chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) phenotypes in COPD patients with frequent exacerbations (FE). In CB or EM phenotypes, COPD patients with FE present several differential clinical characteristics compared to patients with infrequent exacerbations (iFE). On the other hand, the characteristics of ACOS phenotype in patients with FE require more investigation.

Methods

• From November 2015 to October 2016, COPD patients with acute exacerbations were consecutively reviewed.
• After that, patients were divided into FE and infrequent exacerbations (iFE) subgroups.

Results

• An aggregate of one hundred forty-two eligible COPD subjects were reviewed.
• In the CB phenotype subgroup, age, body mass index, forced expiratory volume in 1 second (FEV₁) % predicted, COPD assessment test (CAT), modified Medical Research Council breathlessness measurement (mMRC) dyspnea scale, emphysema scores and arterial carbon dioxide pressure (PaCO₂) were significantly different in subjects with FE when contrasted with those in subjects with iFE of CB.
• In the EM phenotype subgroup, age, CAT, mMRC scores and history of COPD were different in subjects with FE when contrasted with those in CB subjects with iFE.
• Multivariate analysis showed that FEV₁% anticipated (odds ratio [OR] =0.90, P=0.04) and PaCO₂ (OR =1.22, P=0.02) were independent risk factors for FE in COPD with CB phenotype, and CAT (OR =2.601, P=0.001) was the independent risk factor for FE in COPD with EM phenotype.
• However, no significant differences in characteristics were seen in ACOS phenotype subgroups with FE or iFE.